| 摘要 |
PURPOSE:To reduce the size of the whole of a device and obtain full luminous intensity by providing the second airtight container that encloses the first airtight container and filling the sealed space formed between the first and second airtight containers with gas. CONSTITUTION:When a voltage is applied between lead wires 3 and 4, a filament 6 generates heat and emits electrons. Simultaneously the glow discharge of a sealung gas (argon) is started between the tips of the lead wires 3 and 4, the internal temperature of the first airtight container 1 is raised, mercury vapor pressure is raised, and the glow discharge of mercury is started. While the luminous intensity (curve B) of a low pressure mercury lamp from which the second airtight container 7 is removed is slightly excellent around 60 deg.C, the low pressure mercury lamp by this invention maintains almost constant luminous intensity (curve A) at an ambient temperature from +10 to +40 deg.C. The luminous intensity is equal to the maximum luminous intensity of the conventional low pressure mercury lamp. |
